The present invention relates generally to the field of waveguides and more specifically to expansion joints for joining sections of waveguide.
Various tapers have been developed for the TE.sub.01 circular waveguide mode. Expansion sections have also been used in TE.sub.01 mode transmission lines. The expansion sections previously developed require the inside diameter of the expansion section to be tapered to a smaller size for the sliding expansion section and then tapered back to the required guide size. This is the standard procedure using linear tapers. Tapering to a larger diameter requires tapers of a more complex design to minimize generation of the TE.sub.02 circular guide mode. Since larger diameter guide has lower loss, it is desirable for long straight sections. Expansion sections are also often required for long rigid lines. Using two separate components for expansion joints and tapers requires a total of three tapered diameters, four connectors and a length of guide which may be excessive.